[backbencher]

I'm not sure the bullets will stabilize in a shorter barrel unless you're using short ones like the TCM uses.

Uh, I mean, you could just use a faster twist... Some folks are indeed using 5.7 as an EDC, but they are few & far between. Shorter bbls will likely significantly drop velocity, which is the cartridge's raison d'etre.

One big upside to the S&W, & I think I see three disadvantages.

The rotary bbl gas operated locking system, as Kirk noted, will likely ease working of the brass for reloaders, which would significantly drop costs for those folks, particularly if the S&W is coating agnostic, which it might be.

Downsides:

1) The rotary bbl & gas operated action is likely to complicate suppressor installation, unless Smith's gone with a fixed thread on the outer gas sleeve, but we still don't know what additional backpressure will do to the action.

2) Proprietary mags - most other manufacturers have a mag that fits an existing 5.7 carbine on the market, Smith does not yet.

3) Cleaning - looks simple enough, but reloaders may find certain powders are cleaner in the Smith's action, and casual shooters may find certain commercial loads are cleaner or dirtier and require the Smith to be cleaned more often than other action types.

 

[backbencher]

So far as item #1 goes, from what I saw in one review the threads are on the outer barrel sleeve and it doesn't rotate.

That's really good news. Might be able to use .22" cans that are proofed for 5.7 w/o a booster then.

 

[backbencher]

That's what I tell my wife.